Question

If A= {x:x is an even number},B={x:x is a odd number}, C= {x:x is a prime n umber}, D= {x:x is a multiple of 3} Find A-B,B-A,A∪B,A∩B?

Answer 1

A = set of even integer numbers.
B = set of odd integers.
C = prime number set
D = integers which are multiples of 3.

A - B  = A - A Π B = A
       as  A and B are disjoint sets.    A Π  B  = null set φ

B - A  = B  as    same reason as above.

A  U B = I or Z = set of all integers , as an integer is either even or odd.
A U B =  {x : X is an even integer or an odd integer }
           = { x : x is an integer }

A Π B = {x : x is an odd integer and an even integer }
           = φ  null set.